An array of PHP

Array classification:

1. Index Array. The index value starts at 0 and increments sequentially.

2. Declaring an array using the array () function

<?php    //1. Assign a value directly to an array element to declare it    $contact _index[0] = 1;    $contact _index[1] = "Gao MoU";    $contact _index[2] = "a company";    $contact _index[3] = "Beijing";    $contact _index[] = "[email protected]";    Var_dump ($contact _index);    $contact _key["ID"] = "2";    $contact _key["name"] = "peak";    $contact _key["Company"] = "Company B";    $contact _key["email"] = "[email protected]";    Var_dump ($contact _key);    2. Declare an array using the array () function    $contact _key_array = Array (        "ID" = 1;        " Name "= =" Peak One ";        " Company "=" b Company ";        " Email "=" [email protected];    );    Var_dump ($contact _key_array);? >

Traversal of the array:

1.for Statement Traversal array

2.foreach Statement Traversal array

<?php    //Use the For statement to iterate through the array    $cars =array ("Volvo", "BMW", "SAAB");    $arrlength =count ($cars);    for ($i =0; $i < $arrlength; $i + +) {    echo $cars [$i];    echo "<br>";    }   ? ><?php
   The foreach statement iterates through the associative array   $age =array ("Bill" = "+", "steve" = "Notoginseng", "Peter" and "a");   foreach ($age as $x = + $x _value) {   echo "key=". $x. ", value=. $x _value;   echo "<br>";   }? >

Pre-defined arrays

1. It is a special array, no difference in operation mode.

2. Do not declare them, and each PHP script has a default.

3. They take effect automatically in the global scope.

Pre-defined array description

The $_server variable is set by the Web server or is directly associated with the execution environment of the current script

$_env the execution environment commits the variables to the script

$_get a variable submitted to the script via a URL request

$_post the variables submitted to the specimen via the HTTP POST method

$_request variables submitted to the script via the Get,post,cookie mechanism

$_files variables submitted to the script via HTTP POST file upload

$_cookie variables submitted to the script via the HTTP COOKIE method

$_session variables currently registered to the script session

$_globals contains a valid variable that refers to the global scope of each current script, and the key name of the array is the name of the global variable.

Merging arrays

The Array_merge () function merges the arrays together to return an array of unions.

Array Array_merge (array array1 array2.....arrayn)

<?php    $fruits =array ("Apaple", "banana", "pear");    $numbered =array ("1", "2", "3");    $cards =array_merge ($fruits, $numbered);    
    
Array ([0] = apaple [1] = banana [2] = pear [3] = 1 [4] = 2 [5] = 3)
?>

Splitting a fraction group

The Array_slice () function returns a portion of the array, starting with the key offset and ending at the offset+length position

Array array_slice (array array,int offset,[int length])

Offset is positive when starting from the front and negative when starting from the back

<?php    $fruits = Array ("Apple", "Banana", "Orange", "Pear", "Grape", "Lemon", "watermelon");    $subset =array_slice ($fruits, 3);    Print_r ($subset);
    Output
    Array ([0] = Pear [1] = Grape [2] = Lemon [3] = watermelon)?>

<?php
    $fruits = Array ("Apple", "Banana", "Orange", "Pear", "Grape", "Lemon", "watermelon");
    $subset =array_slice ($fruits, 2,-2);
    Print_r ($subset);
    Output
    Array ([0] = Orange [1] = Pear [2] = Grape)
?>

Array header add element:

The Array_unshift function adds elements to the array header

<? PHP   $fruits = Array ("Apple", "Banana", "Orange", "Pear", "Grape", "Lemon");   Array_unshift ($fruits, "AAAA", "BBBB");   Print_r ($fruits);//output//array ([0] = AAAA [1] = BBBB [2] = Apple [3] = = Banana [4] = Orange [5] =&G T Pear [6] = Grape [7] = Lemon)?>

Array header Delete element:

Array_shift Deleting an array header element

<?php   $fruits = Array ("Apple", "Banana", "Orange", "Pear", "Grape", "Lemon");   Array_shift ($fruits);   Print_r ($fruits);//output//array ([0] = Banana [1] = Orange [2] = = Pear [3] = = Grape [4] = Lemon)? ;

Add elements at the end of the array:

The Array_push function adds elements at the end of the array

<?php    $fruits = Array ("Apple", "Banana", "Orange", "Pear", "Grape", "Lemon");    Array_push ($fruits, "AAAA", "BBBB");    Print_r ($fruits);//output//array ([0] = Apple [1] = Banana [2] = Orange [3] = Pear [4] = = Grape [5] =& Gt Lemon [6] = AAAA [7] = BBBB)?>

The trailing element of the array is deleted:

The Array_pop function deletes the trailing element of an array, returning the last element of the array.

<?php   $fruits = Array ("Apple", "Banana", "Orange", "Pear", "Grape", "Lemon");   $result =array_pop ($fruits);   Print_r ($result);   echo "<br>";   Print_r ($fruits);//output//$result  returns lemon//$fruits  returns an array ([0] = Apple [1] = Banana [2] = Orange [ 3] = Pear [4] = Grape)?>

An array of PHP